Detection of Proton Irradiation Damage in 4H-SiC Schottky Diodes Via Electrically Detected Magnetic Resonance and Near-Zero-Field Magnetoresistance

We utilize Electrically Detected Magnetic Resonance (EDMR) and Near-Zero-Field Magnetoresistance (NZFMR) to identify the physical and chemical nature of atomic scale defects generated by proton bombardment of 4H-SiC Schottky diodes. We use EDMR and NZFMR to explore proton irradiation created deep level defects which contribute to trap-assisted tunneling through the Schottky barrier. We measure the spin-dependent response of the deep level defect for both an irradiated and unirradiated diode to compare the effects that proton irradiation has on device performance. We observe that the unirradiated diode has no response, and the irradiated diode has a large response. The maximum change in current (I/I) due to NZFMR is 0.44% which occurs at 1.3V forward bias. The nature of the response is consistent with several reports of spin-dependent trap-assisted tunneling (SDTAT) [11, 15, 23, 24]. The EDMR response has an isotropic g-value of 2.003 and is ~10G wide. We tentatively ascribe this response to a negatively charged silicon vacancy (V_Si-). Our work shows that EDMR and NZFMR have the sensitivity and analytical power to study the physical and chemical nature of point defects caused by particle irradiation in these devices. More Importantly, it suggests that these techniques may be widely applicable to investigations of particle irradiation on semiconductor devices.